Full Grown at What Age?

Well, I'm not sure if this is the right spot for this, but what around what age are kitties usually full-grown? My kitty is HUGE, not fat at all, just tall and long with big strong limbs, and he's only 6 months. He's a domestic shorthair, or so we think. He was feral so we have no idea about his real heritage, but we are starting to wonder if he has one of the 'big breeds' mixed in.

It really depends on the cats line. Maine Coon's don't stop growing until they are 5 to 6 years old. Most domestic cats can be linked back to the Maine Coon because they were one of the very first domestic cats in the United States. Thats not to say that the cats cant be linked to other breeds. The average cat usually is done growing by 1.5 years old. Where as some of the larger domestics seem to grow until they are about 3 or so.

Thanks!

Wow, so this kitty may end up being huge! I've been looking at pics of other breeds to see if he looks a little like some of the others.
He just seems awfully big for a domestic shorthair, but I suppose he could just come from a 'big family'! He has marking very similar to some of the Maine Coons I looked at, but has short hair, so I am guessing he's just a big domestic.

My pepper is huge to, but he is 10 months old. He weighs about 14 pounds and he is 23 inches long. He is the biggest cat in the house!